13-foot marine predator found inside another’s belly in shocking fossil ‘turducken’

Dolphin-like reptiles called ichthyosaurs were thought to pick off small, squishy prey. now a new fossil suggests they may have been early “megapredators.”


240 million years ago, a massive marine reptile swallowed a slightly less massive reptile and died shortly thereafter.

The larger creature—a dolphin-like reptile known as an ichthyosaur—then fossilized with the smaller animal in its belly.

The two remained locked in stone until 2010, then scientists in southwestern China began excavating the fossil.

Now, the scientists say that much of what we thought we knew about life and death in the prehistoric ocean,

Could be upended by this sea monster turducken.

A turducken is an oddity made by cooking a chicken that’s inside a duck that’s inside a turkey.

In the unique fossil, the smaller creature in the ichthyosaur’s belly was a thalattosaur,

Which is ancient marine reptile with a long, skinny body that looked more like a lizard than a fish.

When Ryosuke Motani, a paleontologist at the University of California, Davis, realized there was a nearly complete torso,

From a 13-foot-long thalattosaur bulging from inside the 16-foot-long ichthyosaur’s stomach,

He knew his team was onto something groundbreaking. A study on the fossil was published today in the journal iScience.


A thalattosaur specimen was found inside the stomach of an ichthyosaur.

Ichthyosaurs breathed air and gave birth to live young.

While some species grew to lengths that approached the vastness of a blue whale,

aErly ichthyosaurs like the Guizhouichthyosaurus that Motani examined were smaller, perhaps 13 to 19 feet in length.

These ancient swimmers are thought to have preyed on slippery, squid-like cephalopods,

Using mouths full of dull, grabby teeth to snatch their meals out of the water.

In fact, none of the aquatic animals alive during this time were thought to have tackled large prey;

That sort of apex sea monster was not believed to have evolved until later.

But according to Motani, the newly described fossil suggests that early ichthyosaurs were the Mesozoic era’s first “megapredators,”

Or large animals that prey on other large animals. “They were feeding on animals bigger than humans,” he says.

A prehistoric cold case

Piecing together an event that took place hundreds of millions of years ago comes with several challenges.

For starters, Motani and his team needed to prove that the ichthyosaur actually ate the thalattosaur,

Rather than the smaller marine reptile simply fossilizing on top of the ichthyosaur by sheer happenstance.

“Thankfully, in this case, there’s a way to tell,” he says. The ichthyosaur’s rib cage wraps on top of the prey animal,

Indicating the thalattosaur was in fact a meal.

But what kind of meal is another important question.

The ichthyosaur might have scavenged the carcass of a thalattosaur that died by other means.

Inside the ichthyosaur, however…….